Method of eye protection and means for practicing- the same



l A. B. HURLEY METHOD OF EYE PROTECTION AND MEANS FOR PRACTICING SAME Original Filed Aug. 18. 1924 Sept. 2, 1930.

TIA/TED BAC/(GROUND BLUE-GREEN .30% WH/TE UNDER /NTfN/r/ Reissued Sept. 1930 f Re. 17,789

rUNITED STATES PATENT OFFICE ALBERT B.l HURLEY, OFWNEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, T0 NATIONAL PAPER APROCESS COMPANY, 0F NEW YORK, N. Y.,` A CORPORATION OF DELAWARE METHOD OF EYE PROTECTION AND MEANS FOR PRACTICING- THE Original application iiled August 18, 1924, Serial No. 732,775f3enewed .Tuly 12, 1926. Original No.

1,659,734, dated February 21, 1928. Application for reissue illed February 21, 1929. Serial No. 341,852.

My invention relates to the art of optics and particularly to theapplication of certain principles of balanced colors and bal-y anced intensities with respect to their physiological eifect on the eye and the resultant effect on the nervous system. It has for its object to relieve nerve tension and lessen or prevent fatigue when the eyeis exposed si-` multaneously or in rapid alternation to light of different intensities and different colors, as for example in playing games of cards according to customary methods.

I attain my object, and satisfy the foregoing requirements by regulating the hue, saturation and brightness of the light reflected from the surfaces` exposed to high illamination, and thereby in a manner which will be presently described regulate the percentage difference 'in physiological effect. More specificallyv stated, I use a light filter or color screen for reflecting surfaces which are not required to reflect the full effect of high illumination, and I arrange this color screen so that a certain percentage of white or normal light may be reflected from said surfaces without change. I have found that by regulating the amount of this pure white light that is reflected, the stimulus due thereto can be increased or reduced to any desired degree, without affecting the amount oflight reflected from particular objects such as the spots on cards which require high visibility and therefore call for maximum' illumination and reflection.

Since the terminology of color is not yet standardized the following definitions are -given for the terms hue, saturation, and

brightness, used herein: By hue is meant the color itself as `:suggested by its naine. vThe saturation or purity is a. measure of the-relative amount of white in the color mixture. On' diluting a color with white, tints are obtained; that is tints are unsaturated colors. By brightness is meant the'degree' of intensity of illumination, which can be found by comparing it by means of a photometer with a surface of known brightness, itsrefiection cocilicient for a standard white light being taken into' account in comparing it with other colors in this respect. (See Luckieshk Color and with the added advantage of regulability. Y

The mode of application of my invention to such purpose as a game of cards is illustrated in the accompanying drawings, in which:

Fig. 1 shows a surface treated to break up and subdivide the reflected light, filtering out longer waves from part thereof.

2 shows an enlarged fragment of a surface treated to diffuse the reflected light.

. Fig. 3 is an enlarged fragment of a surface having mixed absorption dots to produce the same result as in Fig. 1.

Fig. 4 is a fragment of. a surface with a pure white background.

Fig. 4 is a diagram illustrating the effect on the eye of the light rays reiiected from Fig. 4.

Fig. 5 is a fragment of a surface with a tinted background.

Fig. 5a is a diagram illustrating the eifect on uthe eye of the light rays 'reflected from Fig. 5.

Fig. 6 is a fragment of a surface with a on the eye of the light rays reflected from Fig. 6.

The filter medium may be constructed in several ways, all based on the same principles, but what now seems to me the best way is illustrated in Figs. 1, 2 andS, wherein I have shown a surface 1 having applied to it a id of light absorbing members 2, which b t eir crossing and interlacing form smal o en squares or white surface. T-he width orthlckness of each of the members 2, and the number of these to the unit of surface determine the dimensions of the enclosed squares and therefore the percentage of pure white light which will be reiected according to the nature of v White ,light reflected can e accurately conthe natural surface. This surface being white this means that the erce'ntage of pure trolled, to produce a proper degree of stimulation of the controlling nerve centers which regulate the'iris or aperture of the eye. It is obvious that if desired the reverse of this arrangement may be used, by applying properly related squares of light absorbing mediunr so as to leave the grid white or 0f the natural color of the surface. I do not consider this however as desirable as the first method for various reasons.

Another way of making the color screen or filter is by producing upon the reflecting surface a mixture or mosaic of white spots "and light absorbing spots in the saine relative proportions as the grid and the squares in the grid of Fig. 3.' A relative measure of fineness is. the photoengravers screen mesh, and I have found that dimensions corresponding to those of 65 to 100 mesh produce v satisfactory results, provided that the width and light absorbing quality of the mesh lines are regulated as hereinbefore pointedout.

The spots on the cards, orthe objects on a sheet thus treated are unaltered, so that the 'normal coefficient of reflection applies to each one according to its own hue, saturation and brightness. The color filter, in other words is used particularly 'on the background. It

is to be recalled that calendered paper or playing card board-is glazed, and even unglazed board if perfectly white hasa very high coefficient vof reflection, reaching .90 or .95. Such reflection from the field is not required in service, and a large amount of eX- cess light is thus thrown off, which produces ta ssimulus which is most important to con- The color lter lwhich I have foundmost effective is one in which the cross lines ab#l sorb practically all the red rays and a con` siderable proportion of the yellow rays, so

that the reflected rays produce the effect of bluish green or greenish blue. The white light` reflected from the squares between the meshes affects this in the following manner.:

Under moderate illumination by white light, which may be assumed to include good artificial illumination, the surface will appear faintly tinted but with a depth-or life which makes the objects or Vsymbols borne thereon assume sharp definition.v Exposed-to strong or high illumination, as by'direct sunlight or a nearby bright tungsten lamp, the

y impression of color vanishes, as the amount of white light reflected increases, and I havefound by actual experiment that the mental impression lof pure white light is produced under strong illumination Vwith an 85 mesh 'color screen; while the strength of the stimulus is reduced well below the point of retinal fatigue or failure of the. iris muscles to act, or so called dazzling. This eiect can be conraves flrmed by holding the surface under test in a fixed position under' high illumination and moving a perfectly Vwhite surface toward it. The eye at once responds to the higher stimulus due to the increased amount of white light and the mental impression of color or shade is produced by comparison with re-V spect to the white surface. As the white surface is then moved away, all impression of color vanishes and within a period varying with the degree of over stimulation, the mental impression again becomes that of pure white light.

For the specific purpose of regulating brightness of the refiected light, the same may be diffused by somewhat breaking thesurface, as indicated in Fig. 2. One reason .for using this means is to compensate for the rays transmitted from the surfaces shown in Figs. 4, 5 and 6. In Fig. 4, a is the white background; an edge view of which is shown in Figur/i". The raysof light transmitted therefrom make for an over intensity, so that the image is not clear upon the retina but as indicated symbolicallyat d', is improperly received by the retina.

In Fig. 5, a is the surface, ground a tinted blue-'green 80% white diluted. This tint although overcoming the fault of the surface of Fig. 4, that is, the resultant over intensity, results in the opposite fault of under intensity, as is symbolized in Fig. 5. The rays are 4transmitted from surface a and passedto the lens band from ythence toward theretina e, but thetransmitting surface being tinted in the aforesaid manner the imageis not clear upon the retina, but as indicated symbolically at d is improperly received by the retina.

In Fig. 6, the background is shown with a pure white surface partially covered by a screen or grid a, shown in the Cfigure greatly enlarged. In practice the individual mem- ;bers of this screen orgrid are not perceptible to the naked eye, being of such dimensions 4as to leave approximately 25% of the pure white surface exposed, which of course will reect pure white light. The screen consti-` tutes a color filter, which I make of a tint known in thetrade as blue green 30% white diluted. Hence those parts of tlie surface which are covered bythe screen or grid refiect only pale blue green light. The effect of this tinted grid with its enclosed and distributed white spaces is to produce a fine mosaic or checkerboard effectof mingled white ,and tinted spots, the white light remaining however undiluted by the'ti'nted having a back-i .i

light, and producing the effect on the retina. and the proper stimulus to adjustment of the iris and lens, due to White light in the quan- -tity thus transmitted. The limit of ineness is that beyond which the mosaic ofwvhite squares is too small to be perceived, and the limit of coarseness is ,that beyond which the total area of White surface exposed and necessary to produce balanced and normal action in the eye is exceeded. I have found in actual practice, using the photoengravers screen mesh as a standard of measurement, that a grid or color filter a2 of the tint mentioned, with its lines and enclosed white squares equal in Width, and of a fineness between eighty five and a hundred per inch, is suitable for my purpose, at reading distance. It will be understood that the area of the White surface exposed or of the tinted surface im- ALBERT B. HURLEY.

posed, as thus expressed, is calculated for the usual reading distance of approximately 14 inches, only. This means that at a greater distance, the mesh may be coarser.

fIt will be understood that I am not limited to the specific means for practicing my method as hereinafter claimed. The gist of the invention lies in the use of a light filter or color screen so arranged' mechanically as to reduce the amount of White light directly reflected from uncovered portions of the background surface, and at the same time to absorb a portion of the stronger. color Waves reaching the covered portions of the surface, so as to reduce retinal fatigue and bring the maximum and minimum stimuli to Within the limits of normal adjustment of the eye.

What I claim is:

. 1. A 'White' reflecting background surface bearing symbols and having imposed upon it a color screen or filter in the form of a grid adapted to uniformly absorb a portion of the longer Waves of light to produce a uniformly distributed into with enclosed and uniformly distributed white portions, the total'area of saidtinted portions and the total area of the White portions being to each other approximately as three to one, and the grid being of a ineness between eighty and one hundred mesh per inch.

2. A White reflecting background surface having imposed upon it a color screen or filter in the form of a grid adapted to uniformly absorb a portion of the longer Waves of light to produce a uniformly distributed tint with enclosed and uniformly distributed untinted portions, the total area of each unit including a tinted area and an untinted area, being such that the unit Will not be separately visible as such.

3. A. background surface having imposed upon it a color screen or filter in the form o a grid adapted to uniformly absorb a portion of the longer Waves of light to produce a uniformly distributed tint with enclosed and uniformly distributed untinted portions,

j qERrlrlcArEorcomCrloN.

Reissuermnf No. 11,789.

farmed september 2; 1930, gol' r- ALBERT n. uULY.

Itis herebyVv certifiedY that error appears in the Vprinted specification of the above numbered patent` requiring correction as4 foilowsV Page 3, line 43,l claim-' l, for the word "into" read tint; and that the said Letters Patent should be read with this correction therein that the slame` hay conform tothe record'of lthe case in the Patent Office.

Signed and sealed this 21st dny of October, D. `193:0.

'l M. J. Moore, (Seal) Acting Commissioner of: Patents? l 

